Team:Shanghai HS/Parts Collection
Part Collection
Favorite basic part
Part: BBa_K3527000
The phoA promoter is repressed by high phosphate concentrations. Under phosphate limited conditions, phoA promoter (basic parts BBa_K3527000) is activated. There are the other two phoA promoter sequence (basic parts: (BBa_K1139200 and BBa_K737023) which are much shorter than that of BBa_K3527000.
Regulation of phoA promoter by phosphate concentration
The function of phoA promoter was evaluated by regulation of transcription of gene of enhanced green fluorescent protein (EGFP). Using this reporting system, we showed that compared with the control, the bacteria containing PhoA-EGFP showed that significant fluorescence intensity difference (Figure 1) in the absence of phosphate in the medium. When the phosphate concentration added into the culture, the fluorescence intensity decreased to a level similar to control culture.
Figure 1. Different concentrations of phosphate were added to the culture medium for treatment, within 15 minutes, compared with the control group, the E. coli containing PhoA-GFP plasmid had a higher detectable fluorescence value in the 0-0.2mM concentration range.
Favorite composite part
Part: BBa_K3527003
BBa_K3585006 is a composite part constituting of enhanced green fluorescent protein gene under control of phoA promoter (basic parts BBa_K3527000). The similar design was seen for composite parts BBa_K1139201 and BBa_K737024. The part BBa_K737024 does not have experimental data showing its function and the part BBa_K1139201 has sufficient data showing its function but no practical application.
Fluorescence intensity of enhanced green fluorescent protein (EGFP) regulated by phosphate concentration
Bacteria containing phoA-EGFP showed that significant fluorescence intensity difference compared to the control in the absence of phosphate in the medium (Figure 1). When the phosphate concentration added into the culture, the fluorescence intensity decreased to a level similar to control culture. In the case of phosphorus deficiency (0-0.2mM), the detectable fluorescence of phoA-EGFP was the most significant difference compared with the control group.
Figure 1. Different concentrations of phosphate were added to the culture medium for treatment, within 15 minutes, compared with the control group, the bacteria containing PhoA-GFP plasmid had a higher detectable fluorescence value in the 0-0.2mM concentration range.
Determination the best of phosphate detection time for phoA-EGFP system
As shown in Figure 2, with the extending of culturing time, the GFP fluorescence signal intensity decreased. This suggests that phoA-EGFP can detect phosphorus deficiency signals in a short period of time (approximately within 1 h). It has great application potential in detection of water environment polluted by phosphate.
Figure 2. Fluorescence intensity of phoA-EGFP system changes with culturing time.
Wechat: Search “PhosFATE”in WeChat